Triode vacuum tube



Feb. 27, 1934. w. G. .WADE

TRIODE VACUUM TUBE Filed NOV. 2 1924 INVENTOR h a/bce 61 1 0023. BY

ATTORNEY WITNESSES: 6.

Patented Feb. 27, 1934 TRIODE VACUUM TUBE Wallace G. Wade, Lancaster, Pa., assignor to A Westinghouse Electric 56 Manufacturing Company, a corporation of Pennsylvania Application November 22, 1924 Serial No. 751,512

2 Claims.

My invention relates to thermionic discharge devices and particularly to such devices as are adapted for the utilization of relatively high powers.

An object of my invention is to provide a thermionic discharge device that is adapted for operation at relatively high powers.

Another object or" my invention is to provide a thermionic discharge device in which the anode is a portion of the evacuated container.

Another object of my invention is to provide a thermionic discharge device having concentric cathode, grid and anode elements and adapted for artificial cooling of the anode member.

Another object of my invention is to provide a thermionic discharge device which may be manufactured with great convenience.

Another object of my invention is to provide a thermionic discharge device in which a grid member is insulatingly supported in an improved manner at both ends thereof.

Another object of my invention is to provide a thermionic discharge device having convenient supporting means for positioning an axial filament within an artificially cooled anode structure.

In the prior art of vacuum tubes, it has been common to construct the electrodes therein in such way as to position them concentrically. Such construction according to the prior art, however, did not make provision for the artificial cooling of the anode structure and, therefore, the energy which could be translated by the device, was limited by the natural cooling of the anode and limited thereby to a relatively few watts.

In the prior art, it has been attempted to produce a thermionic discharge device having means for cooling the anode artificially, but such structures have not been adapted to utilization therewith of a single coaxial filamentary cathode. They have, instead, usually required elaborate looped filaments and anode structures of oval or other shapes rather than cylindrical anodes. My invention provides a structure in which are provided a cylindrical anode with coaxial grid and cathode elements and also, means for artificially cooling.

Other objects and structural details of my invention will be apparent from the following description when read in connection with the acanode, preferably of copper, the ends of which are reduced in thickness to a sharp edge as shown at 2. Vitreous closures 3 and 4, preferably of suitable glass, are sealed to the thinned edges of the anode cylinder 1. Closure 3 has a re-entrant portion 5 upon which is positioned a press 6. Closure 4 has a re-entrant portion '7 and a press 8.

Within the closure 4 is positioned an insulating disk member 9 perforated suitably for the insertion of other members.

A grid 11, which is positioned coaXia-lly within the anode 1, comprises a plurality of lengthwise wire members, of which wires 12 and 13 are shown in the drawing, and ahelical wrapping wire 14 thereabout and attached thereto. An end of each of the lengthwise wires is attached to a supporting band 15 which is positioned upon the re-entrant portion 5 of the closure 3. The other ends of wires 12 and 13 are inserted in perforations 10 in insulating member 9. This construction produces a grid member which partakes of the nature of a truss structure.

Through the press 6 is inserted a seal wire or conducting lead 16, to which is attached one end of a filamentary cathode 17. The other end of cathode 1'7 is attached to a wire member 18 which is also inserted through a perforation in insulating member 9. A portion of wire 18 is formed into a spiral spring 19 which is attached to a supporting member 21 which is connected to a seal, or conducting wire 22 in press 8. As disclosed in Fig. '1, the spring 19 bears against the upper portion of the insulating member 9 and the filament is accordingly additionally supported by the member 9 under suitable tension.

In the operation of my device, it is connected with suitable operating circuits in any manner well known in the prior art. A suitable heating current is thereby passed through cathode 17, by way of seal wires 16 and 22. At an elevated temperature, an electron stream may be caused to pass from cathode 1'7 to anode 1 by the application of a suitable potential therebetween. This electron stream is then subject to control by the grid member 14 in the usual manner.

By the construction described, I am enabled to obtain satisfactory junctions between the metal of anode 1 and the vitreous material of closures 3 and 4. The device is adapted to be evacuated upon the completion of the assembly in any manner well known in the prior art. It is adapted for convenient adjustment of its various elements in the course of assembly by virtue of the visibility of both ends of both the grid and the cathode members through the transparent closures 3 and 4. The outer surface of anode 1 being freely exposed, it is adapted to the application of any artificial cooling medium such as oil or water. Also, the close spacing between the various electrodes reduces the space charge effect, and thereby reduces the internal impedance. Likewise, the close spacing of grid and cathode increases the mutual conductance.

The foregoing structure is particularly convenlent for the assembly of the tube since the electrode mount, comprising the stem 5 with the grid 14 and the cathode 17 mounted thereon, may be inserted from the bottom of the tubular anode 11, and the upper ends of the grid and cathode mounted on the insulating disk 9 before the upper glass closure 4 is sealed, thus permitting easy access for properly locating the upper electrode ends. The flare of the stem 5 may then be sealed to the lower closure member 3 and the disk 9 holding the upper electrode ends may be suitably positioned within the closure 4 by proper indentures in the glass walls, as shown in the drawing. After the electrodes are thus fully located in the positions which they are to have in the finally assembled tube, the upper closure member may be sealed, provision being also made for connecting the upper terminal wire 22 to the upper terminal of the cathode filament 17.

By this means I have produced an improved artificially cooled thermionic discharge device which is capable of utilization with high powers. It is alsoconvenient to assemble because of the accessibility and visibility of the various structural elements.

While I have shown only one embodiment of my invention in the accompanying drawing, it is capable of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be imposed thereon as are indicated in the prior art or in the appended claims.

I claim asmy invention:

1. An electron-discharge device comprising a tubular metallic electrode member, insulating closure members sealed to both ends of said electrode member and constituting therewith a hermetic enclosure, additional electrode means disposed within said tubular electrode and supported at one end solely by means of one of said closure members and insulating means for supporting the other end of said additional electrode means, said insulating means being supported solely by the other of said closure members independently of that end of saidother closure member which is farthest removed from said tubular electrode.

2. An electron-discharge device comprising a tubular metallic electrode member, insulating closure members sealed to both ends of said elec trode member and constituting therewith a hermetic enclosure, additional electrode means in cluding a cathode and a control electrode disposed within said tubular electrode and supported at one end solely by means of one of said closure members and insulating means for supporting the other end of said additional electrode means, said insulating means being supported solely by the other of said closure members independently of that end of said other closure member which is farthest removed from said tubular electrode.

WALLACE G. WADE. 

